Method for modifying electron spin resonance signals from hydrocarbon crude

Abstract

Method for enhancing electron spin resonance signals from crude petroleum by contacting the crude petroleum with a chemical which effects the population of free radical asphaltenes in the crude petroleum. The enhancement is in a positive sense when the chemical is a halogen and particularly iodine. The enhancement is in a negative sense (suppression) when the chemical is ferric chloride.

What is claimed is: 
     
       1. A method for enhancing electron spin resonance signals from crude petroleum comprising contacting said samples with a halogen or ferric chloride to affect the number of the population of free radical asphaltenes in said crude petroleum while detecting said electron spin resonance signals. 
     
     
       2. The method of claim 1 wherein ferric chloride is added to decrease the population of free radicals and suppress the detected electron spin resonance signal. 
     
     
       3. The method of claim 2 wherein said ferric chloride is in a solution from the group including benzene, toluene, xylene, or carbon tetrachloride. 
     
     
       4. The method of claim 1 wherein halogen is added to increase the population of free radicals and enhance the detected electron spin resonance signals. 
     
     
       5. The method of claim 4 wherein said halogen is iodine. 
     
     
       6. The method of claim 5 wherein said iodine is a fluid solution. 
     
     
       7. The method of claim 4 wherein said crude petroleum is associated with samples of earth formations in which crude petroleum has been present and said samples are contacted with said enhancing halogen to distinguish electron spin resonance signals from electrons within crude petroleum on said sample from electron spin resonance signals from electrons within said earth formation constituent materials. 
     
     
       8. The method of claim 7 wherein a quantitative measure of crude petroleum within said earth formation sample is made by measuring the magnitude of enhancement of said electron spin resonance signal in response to contacting said earth formation sample with said halogen.